肥大细胞在葡聚糖硫酸钠诱导大鼠结肠炎中的致炎作用研究

目的 研究肠黏膜且巴大细胞(IMMC)在葡聚糖硫酸钠(DSS)诱导结肠炎时的致炎作用。方法 SD大鼠18只,随机分为DSS诱导大鼠结肠炎模型组(10只)和正常对照组(8只)。1周内模型组饮用3％DSS溶液,对照组饮水,观察大鼠的腹泻、便血症状及结肠组织学改变,用荧光法测定结肠组织组胺浓度,ELISA法测定结肠组织肿瘤坏死因子-a(TNF -a)和前列腺素E2(PGE2)水平.组化法对IMMC染色并记数。结果 DSS诱导的模型组第7天开始出现腹泻、便血,结肠黏膜组织学检查有明显损伤,和对照组比较:结肠组织组胺水平降低,TNF-a和PGE2显著升高,IMMC计数增多(P均<0.05),脱颗粒现象明显。结论结肠IMMC具有明显的致炎作用,其机制是IMMC活化及促组胺释放,引发肥大细胞--细胞因子级联反应,促进TNF-a和PGE2的生成,导致腹泻,便血等症状。

Study on the activity of intestinal mucosal mast cells in rats with dextran sulfate sodium induced colitis

Objective To study on the activity of intestinal mucosal mast cells (IMMC) in dextran sulfate sodium ( DSS) induced colitis of rats. Methods Acute colitis was induced by giving 3% DSS orally. Eighteen male rats were randomized into DSS group ( n = 10 ) and normal control group ( n = 8). The rats in DSS control group drank 3% DSS solution from day 1 to day 7; those in normal control group drank water at random. Diarrhea and bloody stool as well as colonic histology were observed. The levels of colonic tissue histamine, tumor necrosis factor-a (TNF-a) and Prostaglandin E2 ( PGE2) determined with fluorimetry and ELISA, and the expression of IMMC in colonic tissue was detected by histochemical stain method. Results Compared with normal control group, the inflammatory symptoms and histologjcal damages of colonic mucosa in DSS group were significantly presented. The level of histamine in colonic tissue was significantly reduced (P < 0. 05 ) ; the tissue levels of TNF-a, PGE2 and the expression of IMMC in colonic tissue were significantly elevated (P<0.05 or P< 0.01). Conclusion The data suggest that intestinal mucosal mast cell have the ability of inducing inflammatory action on experimental colitis through the mechanism of activating IMMC and promoting the release of histamine, initiating the reactions between mast cells and cellular factors, resulted in increasing the production of TNF-a and PGE2 and symptoms of diarrhea and bloody stool.